21205626 has 16 divisors (see below), whose sum is σ = 45673824. Its totient is φ = 6524784.

The previous prime is 21205621. The next prime is 21205633. The reversal of 21205626 is 62650212.

It is a junction number, because it is equal to n+sod(n) for n = 21205596 and 21205605.

It is not an unprimeable number, because it can be changed into a prime (21205621) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 135856 + ... + 136011.

It is an arithmetic number, because the mean of its divisors is an integer number (2854614).

Almost surely, 2^21205626 is an apocalyptic number.

21205626 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21205626 is an abundant number, since it is smaller than the sum of its proper divisors (24468198).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21205626 is a wasteful number, since it uses less digits than its factorization.

21205626 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 271885.

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 21205626 is about 4604.9566773206. The cubic root of 21205626 is about 276.7899809960.

Adding to 21205626 its reverse (62650212), we get a palindrome (83855838).

The spelling of 21205626 in words is "twenty-one million, two hundred five thousand, six hundred twenty-six".